Accession Number : AD0803198

Title :   COMPOUNDS WITH DEFECT STRUCTURES.

Descriptive Note : Progress rept. no. 6, 1 Apr-30 Sep 66,

Corporate Author : POLYTECHNIC INST OF BROOKLYN NY

Personal Author(s) : Banks, E. ; Abbruscato, V. ; Tashima, N. ; Greenblatt, M. ; Schwartz, R. W.

Report Date : 30 SEP 1966

Pagination or Media Count : 9

Abstract : Study of the concentration dependence of the intensity ratio of the 977 millimicron to the 965 millimicron absorption peaks shows the lower energy peak to be strongly non-linear. This suggests, that the peak at 977 millimicron is due to a complex center and permits assignment of the remaining spectrum to Yb3+ largely in cubic sites. Fluorescence spectra have been observed in Eu, Sm and Tb-doped CdF2, and phosphorescence and thermoluminescence have also been observed. Diffusion of sulfur into CdF2:Eu, increases the fluorescence intensity, while simplifying the emission spectrum. LaMn0.5Cr0.5O3 and LaMn0.5Cr0.5O2.5F0.5 both crystallize as nearly cubic perovskites. The former has a magnetic moment of about 1.4 micron/mole, while the latter has a moment of about 3 micron which is 75% of the value to be expected if it were ferromagnetic. Infrared spectra of the chlorospodiosites, Ca2PO4Cl and Ca2CrO4Cl have been analyzed and fit the assignment of C2v symmetry to the tetrahedra. Optical absorption spectra in the visible and UV regions, for a crystal of Ca2PO4Cl containing about 1% Ca2CrO4Cl at 77 K, have been fairly well correlated with a molecular orbital scheme proposed by Ballhausen and Liehr. ESR measurements are consistent with all the other structural data; the 'g' value and hyperfine structure establish the dz2 orbital as the ground state. (Author)

Descriptors :   (*ABSORPTION SPECTRA, RARE EARTH ELEMENTS), CRYSTAL DEFECTS, FLUORIDES, FERRITES, PHOSPHORESCENCE, LUMINESCENCE, INFRARED SPECTRA, CRYSTAL STRUCTURE, SYMMETRY(CRYSTALLOGRAPHY), HYPERFINE STRUCTURE, CADMIUM, FLUORESCENCE, GROUND STATE, ATOMIC ENERGY LEVELS.

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE